Cost effectiveness analysis of a population based screening programme for asymptomatic Chlamydia trachomatis infections in women by means of home obtained urine specimens

Evaluation of Chlamydia trachomatis screening from the perspective of health economics: a systematic review

Background

Most Chlamydia trachomatis (CT) infections are asymptomatic. The infection can persist and lead to severe sequelae. Therefore, screening for CT can primarily prevent serious sequelae.

Aim

To systematically evaluate CT screening from the perspective of health economics, summarize previous findings from different target populations, and make practical recommendations for developing local CT screening strategies.

Methods

PubMed, Web of Science, Embase, Cochran Library, and National Health Service Economic Evaluation Database (Ovid) were searched from January 1, 2000, to March 4, 2023. Studies reporting the cost-effectiveness, cost-benefit, or cost-utility of CT screening were eligible to be included. A narrative synthesis was used to analyze and report the results following the PRISMA guidelines. The Consensus on Health Economic Criteria (CHEC) list was used to assess the methodological quality of included studies.

Results

Our review finally comprised 39 studies addressing four populations: general sexually active people (n = 25), pregnant women (n = 4), women attending STD and abortion clinics (n = 4), and other high-risk individuals (n = 6). The total number of participants was ~7,991,198. The majority of studies assessed the cost-effectiveness or cost-utility of the screening method. The results showed that the following screening strategies may be cost-effective or cost-saving under certain conditions: performing CT screening in young people aged 15-24 in the general population, military recruits, and high school students; incorporating CT screening into routine antenatal care for pregnant women aged 15-30; opportunistic CT screening for women attending STD and abortion clinics; home-obtained sampling for CT screening using urine specimens or vaginal swab; performing CT screening for 14-30-year-old people who enter correctional institutions (i.e., jail, detention) as soon as possible; providing CT screening for female sex workers (FSWs) based on local incidence and prevalence; adding routine CT screening to HIV treatment using rectal samples from men who have sex with men (MSM).

Conclusion

We found that CT screening in general sexually active people aged 15-24, military recruits, high school students, pregnant women aged 15-30, women attending STD and abortion clinics, people entering jail, detention, FSWs, and MSM has health economic value. Due to the different prevalence of CT, diversities of economic conditions, and varying screening costs among different populations and different countries, regions, or settings, no uniform and standard screening strategies are currently available. Therefore, each country should consider its local condition and the results of health economic evaluations of CT screening programs in that country to develop appropriate CT screening strategies.

Assessing the costs and outcomes of control programmes for sexually transmitted infections: a systematic review of economic evaluations

OBJECTIVE

To identify economic evaluations of interventions to control STIs and HIV targeting young people, and to assess how costs and outcomes are measured in these studies.

DESIGN

Systematic review.

DATA SOURCES

Seven databases were searched (Medline (Ovid), EMBASE (Ovid), Web of Science, PsycINFO, NHS Economic Evaluation Database, NHS Health Technology Assessment and Database of Abstracts of Reviews of Effects) from January 1999 to April 2019. Key search terms were STIs (chlamydia, gonorrhoea, syphilis) and HIV, cost benefit, cost utility, economic evaluation, public health, screening, testing and control.

REVIEW METHODS

Studies were included that measured costs and outcomes to inform an economic evaluation of any programme to control STIs and HIV targeting individuals predominantly below 30 years of age at risk of, or affected by, one or multiple STIs and/or HIV in Organisation for Economic Co-operation and Development countries. Data were extracted and tabulated and included study results and characteristics of economic evaluations. Study quality was assessed using the Philips and BMJ checklists. Results were synthesised narratively.

RESULTS

9530 records were screened and categorised. Of these, 31 were included for data extraction and critical appraisal. The majority of studies assessed the cost-effectiveness or cost-utility of screening interventions for chlamydia from a provider perspective. The main outcome measures were major outcomes averted and quality-adjusted life years. Studies evaluated direct medical costs, for example, programme costs and 11 included indirect costs, such as productivity losses. The study designs were predominantly model-based with significant heterogeneity between the models.

DISCUSSION/CONCLUSION

None of the economic evaluations encompassed aspects of equity or context, which are highly relevant to sexual health decision-makers. The review demonstrated heterogeneity in approaches to evaluate costs and outcomes for STI/HIV control programmes. The low quality of available studies along with the limited focus, that is, almost all studies relate to chlamydia, highlight the need for high-quality economic evaluations to inform the commissioning of sexual health services.

A cost-effectiveness analysis of the Chlamydia Monday - A community-based intervention to decrease the prevalence of chlamydia in Sweden

Aims: The study was undertaken to assess the cost-effectiveness of the Chlamydia Monday, 2007. This is a community-based intervention aimed at reducing the prevalence of chlamydia by information and increased availability of testing, treatment and contact tracing in Stockholm. The aim was to analyze the cost-effectiveness by estimating costs, savings and effects on health associated with the intervention, and to determine if cost-effectiveness varies between men and women. Methods: A societal perspective was adopted, meaning all significant costs and consequences were taken into consideration, regardless of who experienced them. A cost-effectiveness model was constructed including costs of the intervention, savings due to avoiding potential costs associated with medical sequels of chlamydia infection, and health gains measured as quality adjusted life years (QALY). Sensitivity analyses were done to explore model and result uncertainty. Results: Total costs were calculated to be 66,787.21; total savings to 30,370.14; and total health gains to 9.852324 QALYs (undiscounted figures). The discounted cost per QALY was 8,346.05 (10,810.77/QALY for women and 6,085.35/QALY for men). Sensitivity analyses included changes in effectiveness, variation of prevalence, reduced risk of sequel progression, inclusion of prevented future production loss and shortened duration for chronic conditions. The cost per QALY was consistently less than 50,000, which is often regarded as cost-effective in a Swedish context. Conclusions: The Chlamydia Monday has been demonstrated by this study to be a cost-effective intervention and should be considered a wise use of society’s resources.

Development and Evaluation of GIS-Based Chlamydia Trachomatis Intervention Policy in Illinois

Chlamydia trachomatis is the most prevalent infectious disease in the United States. Complications include pelvic inflammatory disease (PID), ectopic pregnancy, and infertility. The cost of PID in 1998 was estimated at greater than $1.9 billion. Screening intervention strategies are often consumed by those at low risk. The objective of this study is the development of a more cost-effective intervention strategy by employing Geographic Information Systems and Census Bureau demographic data in selected Local Health Departments in Illinois. Case studies of intervention activities at the state and local level were performed. An evaluability assessment model of current inputs, processes and outcomes was created. A proposed model utilizing additional state inputs was developed and tested. Interventions were evaluated for effectiveness in reducing the incidence of Chlamydia trachomatis. Societal cost effectiveness analysis was also performed. The proposed model was tested in 2006. Results indicate that only minimal changes in annual incidence are required for GIS-augmented interventions to be cost-effective.

Diagnostic challenges of sexually transmitted infections in resource-limited settings

The global burden of sexually transmitted infections (STIs) is highest in the developing world where access to laboratory services is limited. Sophisticated laboratory diagnostic tests using noninvasive specimens have enabled developed countries to screen and diagnose curable STIs in a variety of settings, but control programs in resource-limited settings continue to struggle to find simple rapid tests that can provide adequate performance in the absence of laboratory services. While recent technological advances and investments in research and development may soon yield improved STI tests that can make an impact, these tests will need to be deployed within a health system that includes: regulatory oversight, quality assurance, good supply-chain management, effective training, information systems and a sound surveillance system to monitor disease trends, inform policy decisions and assess the impact of interventions.

Novel approach to an effective community-based chlamydia screening program within the routine operation of a primary healthcare service

Background: A prospective study was undertaken to develop an evidence-based outreach chlamydia screening program and to assess the viability and efficiency of this complementary approach to chlamydia testing within the routine operations of a primary healthcare service. Methods: A primary healthcare service based in Townsville, Queensland, Australia, identified high-prevalence groups for chlamydia in the community. Subsequently, a series of outreach clinics were established and conducted between August 2004 and November 2005 at a defence force unit, a university, high school leavers’ festivities, a high school catering for Indigenous students, youth service programs, and backpacker accommodations. Results: All target groups were easily accessible and yielded high participation. Chlamydia prevalence ranged between 5 and 15% for five of the six groups; high school leavers had no chlamydia. All participants were notified of their results and all positive cases were treated (median treatment interval 7 days). Five of the six assessed groups were identified as viable for screening and form the basis for the ongoing outreach chlamydia screening program. Conclusion: The present study developed an evidence-based outreach chlamydia screening program and demonstrated its viability as a complementary approach to chlamydia testing within the routine operations of the primary healthcare service, i.e. without the need for additional funding. It contributes to the evidence base necessary for a viable and efficient chlamydia management program. Although the presented particulars may not be directly transferable to other communities or health systems, the general two-step approach of identifying local high-risk populations and then collaborating with community groups to access these populations is.

Cost-effectiveness of screening strategies for Chlamydia trachomatis using cervical swabs, urine, and self-obtained vaginal swabs in a sexually transmitted disease clinic setting

BACKGROUND

We evaluated the cost-effectiveness of Chlamydia screening strategies that use different methods of specimen collection: cervical swabs, urines, and self-obtained vaginal swabs.

METHODS

A decision analysis was modeled for a hypothetical cohort of 10,000 per year of women attending sexually transmitted disease (STD) clinics. Incremental cost-effectiveness of 4 screening strategies were compared: 1) Endocervical DNA probe test (PACE2, Gen-Probe), 2) Endocervical AC2 (Aptima Combo 2, Gen-Probe), 3) Self-Obtained Vaginal AC2, and 4) Urine AC2. Sensitivities of the vaginal, urine, and cervical AC2 tests were derived from 324 women attending STD clinics. The primary outcome was cases of pelvic inflammatory disease prevented. The model incorporated programmatic screening and treatment costs and medical cost savings from sequelae prevented.

RESULTS

Chlamydia prevalence in the sampled population was 11.1%. Sensitivities of vaginal, urine, and cervical AC2 were 97.2%, 91.7%, and 91.7%, respectively. The sensitivity of the DNA probe was derived from the literature and estimated at 68.8%. The self-obtained vaginal AC2 strategy was the least expensive and the most cost-effective, preventing 17 more cases of pelvic inflammatory disease than the next least expensive strategy.

CONCLUSIONS

Use of a vaginal swab to detect Chlamydia in this STD clinic population was cost-saving and cost-effective.

Should asymptomatic men be included in chlamydia screening programs? Cost-effectiveness of chlamydia screening among male and female entrants to a national job training program

OBJECTIVE

To compare the cost-effectiveness of various chlamydia screening strategies within a population of male and female youth entering a national job training program.

STUDY DESIGN

Cost-effectiveness analysis of various chlamydia screening strategies among a cohort of 4000 female and male New England job training students. Strategies for women include (a) no screening, (b) universal endocervical DNA probe screening, (c) universal urine based NAAT screening, and (d) universal endocervical NAAT screening. Strategies for men include (a) no screening, (b) selective urine NAAT screening of leukocyte esterase (LE)-positive urines, and (c) universal urine-based NAAT screening.

RESULTS

Universal endocervical NAAT screening of women and universal urine NAAT screening of men were the most effective and cost-effective strategies individually and in combination. Endocervical NAAT screening of women prevented 23 more cases of PID and saved $27,000 more than endocervical DNA probe screening. Likewise, universal urine NAAT screening of men prevented 21 more cases of PID in their female partners and saved $16,000 more than selective urine NAAT screening of LE positive men.

CONCLUSIONS

Use of a sensitive NAAT to screen both men and women for chlamydia upon entry to a National Job Training Program is cost-effective, cost-saving, and provides a public health opportunity to substantially reduce chlamydia infections among youth at risk for sexually transmitted diseases.

Relationship of cytopathology and cervical infection to outcome of in-vitro fertilization and embryo transfer

OBJECTIVE

To determine whether a relationship exists between in-vitro fertilization and embryo transfer (IVF-ET) outcome and cervical infection or presence of human papillomavirus (HPV).

METHOD

Cervical scrapes, digital colposcopies, and cervical biopsies were performed in 1044 Chinese women undergoing IVF for tubal infertility or, in their partners, abnormal semen. The pregnant (n=415) and nonpregnant (n=629) groups differed neither in clinical signs of cervical inflammation nor in rate of HPV detection.

RESULTS

There were no associations between IVF-ET outcome and infection rate, degree of cytopathologic abnormality, detection of HPV, or results of digital colposcopy and cervical biopsy. Cytologic results did not correlate with any of the clinical parameters of IVF-ET.

CONCLUSIONS

No association was found between IVF-ET outcome and cervical infection, cytopathologic result, HPV detection, or result from the colposcopy or biopsy. Extensive testing and treatment for cervical infection do not appear necessary in IVF-ET candidates.

One to one interventions to reduce sexually transmitted infections and under the age of 18 conceptions: a systematic review of the economic evaluations

OBJECTIVE

To systematically review and critically appraise the economic evaluations of one to one interventions to reduce sexually transmitted infections (STIs) and teenage conceptions.

DESIGN

Systematic review.

DATA SOURCES

Search of four electronic bibliographic databases from 1990 to January 2006. Search keywords included teenage, pregnancy, adolescent, unplanned, unwanted, cost benefit, cost utility, economic evaluation, cost effectiveness and all terms for STIs, including specific diseases.

REVIEW METHODS

We included studies that evaluated a broad range of one to one interventions to reduce STIs. Outcomes included major outcomes averted, life years and quality adjusted life years (QALY). All studies were assessed against quality criteria.

RESULTS

Of 3,190 identified papers, 55 were included. The majority of studies found one to one interventions to be either cost saving or cost effective, although one highlighted the need to target the population to receive post-exposure prophylaxis to reduce transmission of HIV. Most studies used a static approach that ignores the potential re-infection of treated patients.

CONCLUSION

One to one interventions have been shown to be cost saving or cost effective but there are some limitations in applying this evidence to the UK policy context. More UK research using dynamic modelling approaches and QALYs would provide improved evidence, enabling more robust policy recommendations to be made about which one to one interventions are cost effective in reducing STIs in the UK setting. The results of this review can be used by policy makers, health economists and researchers considering further research in this area.

Chlamydia trachomatis load at matched anatomic sites: implications for screening strategies

Urethral and endocervical swabs and self-collected vaginal swabs (SCVSs) and urine specimens are all used as samples for diagnosis of urogenital infection with Chlamydia trachomatis. We have now determined chlamydial organism load in matched specimens from different anatomic sites and examined its relation to clinical signs and symptoms in men and women. Organism load was measured with assays based on the ligase chain reaction or real-time PCR analysis. The mean organism loads in 58 infected men were 1,200 and 821 elementary bodies (EBs) per 100 microl of sample for first-void urine (FVU) and urethral swabs, respectively (P>0.05). Organism load in FVU samples or urethral swabs was positively associated with symptoms (P<0.01) and clinical signs (P<0.01) in men. The mean organism loads in 73 infected women were 2,231, 773, 162, and 47 EBs/100 microl for endocervical swabs, SCVSs, urethral swabs, and FVU samples, respectively (P<0.001 for each comparison). Only the presence of multiple symptoms or clinical signs was associated with organism load in women. These results show that FVU is a suitable noninvasive sample type for men, given the fact that its chlamydial load did not differ significantly from that of urethral swabs. Given their higher organism load compared with FVU, SCVSs are the preferred noninvasive sample type for women.

Healthcare and patient costs of a proactive chlamydia screening programme: the Chlamydia Screening Studies project

BACKGROUND AND OBJECTIVE

Most economic evaluations of chlamydia screening do not include costs incurred by patients. The objective of this study was to estimate both the health service and private costs of patients who participated in proactive chlamydia screening, using mailed home-collected specimens as part of the Chlamydia Screening Studies project.

METHODS

Data were collected on the administrative costs of the screening study, laboratory time and motion studies and patient-cost questionnaire surveys were conducted. The cost for each screening invitation and for each accepted offer was estimated. One-way sensitivity analysis was conducted to explore the effects of variations in patient costs and the number of patients accepting the screening offer.

RESULTS

The time and costs of processing urine specimens and vulvo-vaginal swabs from women using two nucleic acid amplification tests were similar. The total cost per screening invitation was 20.37 pounds (95% CI 18.94 pounds to 24.83). This included the National Health Service cost per individual screening invitation 13.55 pounds (95% CI 13.15 pounds to 14.33) and average patient costs of 6.82 pounds (95% CI 5.48 pounds to 10.22). Administrative costs accounted for 50% of the overall cost.

CONCLUSIONS

The cost of proactive chlamydia screening is comparable to those of opportunistic screening. Results from this study, which is the first to collect private patient costs associated with a chlamydia screening programme, could be used to inform future policy recommendations and provide unique primary cost data for economic evaluations.

Screening for Chlamydia trachomatis: a systematic review of the economic evaluations and modelling

OBJECTIVE

To review systematically and critically, evidence used to derive estimates of costs and cost effectiveness of chlamydia screening.

METHODS

Systematic review. A search of 11 electronic bibliographic databases from the earliest date available to August 2004 using keywords including chlamydia, pelvic inflammatory disease, economic evaluation, and cost. We included studies of chlamydia screening in males and/or females over 14 years, including studies of diagnostic tests, contact tracing, and treatment as part of a screening programme. Outcomes included cases of chlamydia identified and major outcomes averted. We assessed methodological quality and the modelling approach used.

RESULTS

Of 713 identified papers we included 57 formal economic evaluations and two cost studies. Most studies found chlamydia screening to be cost effective, partner notification to be an effective adjunct, and testing with nucleic acid amplification tests, and treatment with azithromycin to be cost effective. Methodological problems limited the validity of these findings: most studies used static models that are inappropriate for infectious diseases; restricted outcomes were used as a basis for policy recommendations; and high estimates of the probability of chlamydia associated complications might have overestimated cost effectiveness. Two high quality dynamic modelling studies found opportunistic screening to be cost effective but poor reporting or uncertainty about complication rates make interpretation difficult.

CONCLUSION

The inappropriate use of static models to study interventions to prevent a communicable disease means that uncertainty remains about whether chlamydia screening programmes are cost effective or not. The results of this review can be used by health service managers in the allocation of resources, and health economists and other researchers who are considering further research in this area.

Productivity Losses Attributable to Untreated Chlamydial Infection and Associated Pelvic Inflammatory Disease in Reproductive-Aged Women

BACKGROUND AND OBJECTIVES

The productivity losses attributable to disease-related morbidity and mortality impose a burden on society in general and on employers in particular. A reliable assessment of the productivity losses associated with untreated infection with Chlamydia trachomatis (Ct) would complement earlier work on direct medical costs and contribute to an estimate of the full cost of chlamydial disease.

GOAL

The goal of this study was to estimate the discounted lifetime productivity losses attributable to untreated chlamydial infection in reproductive-aged women.

STUDY DESIGN

We developed a cost model using Monte Carlo methods to estimate the lifetime discounted productivity losses attributable to untreated lower genital tract Ct infection among reproductive-aged women. The model considered the impact of disability resulting from acute pelvic inflammatory disease (PID) associated with untreated Ct infection and from the sequelae of acute PID, including chronic pelvic pain, ectopic pregnancy, and infertility. To accommodate disparate Ct infection rates and labor market characteristics across age groups, we matched age-based risk factors for Ct infection with labor market patterns. Data sources included the 2001 National Chlamydia Surveillance Data, the 2001 Current Population Survey, and published literature.

RESULTS

Estimates indicate that the mean weighted productivity losses per untreated Ct infection were approximately US dollars 130 (in year 2001 dollars). Mean weighted productivity losses per case of acute PID were estimated at US dollars 649. Estimated productivity losses were highly correlated with age, reflecting age-dependent differences in labor market characteristics.

CONCLUSIONS

The productivity losses attributable to untreated infection with Ct and to sequelae of this infection form a substantial portion of the total economic burden of disease. Effective programs to prevent chlamydial infection and effective screening, diagnosis, and treatment of Ct-infected women may reduce productivity losses and substantially lessen the economic burden of disease to employers.

Prediction of costs, effectiveness, and disease control of a population-based program using home sampling for diagnosis of urogenital Chlamydia trachomatis Infections

OBJECTIVE

To estimate the incremental effects and costs of a home sampling screening approach for Chlamydia trachomatis over the current in-office screening practice in Denmark.

GOALS

To assess the effect of a new screening strategy.

STUDY DESIGN

A dynamic Monte Carlo model estimated prevalence and incidence over 10 years for a home sampling screening program and the current in-office screening. Subsequently, the incremental number of major outcomes averted (MOA) and the related direct and indirect costs were estimated.

RESULTS

Infection prevalence after 10 years was 1.0% with a home sampling program and 4.2% with the current in-office screening practice. The total costs per MOA reached 3186 US dollars during the first year of the home sampling strategy, but in year 4, the accumulated indirect costs offset the direct costs, and the program henceforth saved society costs.

CONCLUSIONS

Home sampling should be considered a relevant alternative to the current practice of in-office screening.

Systematic screening for Chlamydia trachomatis: estimating cost-effectiveness using dynamic modeling and Dutch data

OBJECTIVE

To estimate the cost-effectiveness of a systematic one-off Chlamydia trachomatis (CT) screening program including partner treatment for Dutch young adults.

METHODS

Data on infection prevalence, participation rates, and sexual behavior were obtained from a large pilot study conducted in The Netherlands. Opposite to almost all previous economic evaluations of CT screening, we developed a dynamic Susceptible-Infected-Susceptible (SIS) model to estimate the impact of the screening program on the incidence and prevalence of CT in the population. SIS models are widely used in epidemiology of infectious diseases, for modeling the transmission dynamics over time. Subsequently, a predictive decision model was used to calculate the complications averted by the screening program. Cost-effectiveness was expressed as the net costs per major outcome averted (MOA) and was estimated in the baseline analysis and in sensitivity analysis.

RESULTS

The overall prevalence decreased from 1.79% to 1.05% as a result of the screening program directed at both men and women. The program costs were mainly offset by the averted costs, although not fully. Resulting net costs per MOA were 373 euro sin the baseline analysis. Sensitivity analysis showed that partner treatment and sending a reminder are important aspects improving cost-effectiveness. Additionally, restricting the screening to women only was estimated to save costs.

CONCLUSIONS

Our cost-effectiveness analysis shows that the Dutch society has net to pay for the prevention of CT-complications through screening young men and women. One could argue although that 373 euros per MOA presents a reasonable cost. A screening program consisting of screening women only should always be adopted from a pharmacoeconomic point of view. Our dynamic approach appreciates better the specific characteristics of an infectious disease, such as CT.

The cost effectiveness of screening for genital Chlamydia trachomatis infection in Australia

Background: In Australia, there is no published study on the cost effectiveness of screening for chlamydia. The aim of this study was to examine the cost effectiveness of a hypothetical screening programme for chlamydia based on annual opportunistic testing of all women 25 years of age or younger consulting a general practitioner, compared with no screening. Methods: A decision–analytic modelling approach was used to determine the incremental cost effectiveness ratio (ICER) of screening compared with no screening over 25 years. The analysis measured Australian health-care costs and benefits were assessed in terms of quality-adjusted life years (QALYs). Results: The analysis resulted in a cost per QALY of $2968 for screening. One-way sensitivity analyses on all variables, and multi-way sensitivity analyses on some variables, showed a wide range for the cost effectiveness, from dominance (where screening is effective and saves money overall) to an ICER of $67 715 per QALY. Conclusions: The results indicate that annual opportunistic screening for chlamydia in women under 25 is a potentially worthwhile undertaking. However, the analysis also highlights uncertainties around the natural history of chlamydia and the effectiveness of chlamydia screening. Given these uncertainties, the need for further primary data collection in these areas becomes apparent.

Adherence of Pharmacoeconomic Studies to National Guidelines in the Netherlands

OBJECTIVE

This study examines the adherence of Dutch pharmacoeconomic studies to the national guidelines of conducting a pharmacoeconomic evaluation.

METHODS

Dutch guidelines for pharmacoeconomic research were issued in 1999. All Dutch pharmacoeconomic studies that were published in English during 2000-2002 were selected for our review. Two reviewers examined each study for relevance and compared each study with the nine methodological guidelines selected.

RESULTS

It was found that 29 studies satisfied the inclusion criteria. The societal perspective was taken in 13 out of the 29 studies (45%), an adequate time period of analysis was chosen in 21 (72%), effectiveness was explicitly differentiated from efficacy in 17 (59%), an incremental analysis was performed in 23 (79%), costs, benefits and health gains were discounted in 24 (83%), effectiveness was expressed in LYGs or QALYs in 16 (55%), reference prices were used in 8 (28%), subgroup analysis was presented in 13 (45%) and sensitivity analysis was included in 26 (90%).

CONCLUSIONS

In this review we found that the adherence of studies to some of the Dutch guidelines for pharmacoeconomic studies is fair. However, major improvements are required with respect to the adoption of the societal perspective, presentation of adequate subgroup analyses and application of reference prices.

Can we evaluate population screening strategies in UK general practice? A pilot randomised controlled trial comparing postal and opportunistic screening for genital chlamydial infection

STUDY OBJECTIVE

To assess whether opportunistic and postal screening strategies for Chlamydia trachomatis can be compared with usual care in a randomised trial in general practice.

DESIGN

Feasibility study for a randomised controlled trial.

SETTING

Three West of Scotland general medical practices: one rural, one urban/deprived, and one urban/affluent.

PARTICIPANTS

600 women aged 16-30 years, 200 from each of three participating practices selected at random from a sample of West of Scotland practices that had expressed interest in the study. The women could opt out of the study. Those who did not were randomly assigned to one of three groups: postal screening, opportunistic screening, or usual care.

RESULTS

38% (85 of 221) of the approached practices expressed interest in the study. Data were collected successfully from the three participating practices. There were considerable workload implications for staff. Altogether 124 of the 600 women opted out of the study. During the four month study period, 55% (81 of 146) of the control group attended their practice but none was offered screening. Some 59% (80 of 136) women in the opportunistic group attended their practice of whom 55% (44 of 80) were offered screening. Of those, 64% (28 of 44) accepted, representing 21% of the opportunistic group. Forty eight per cent (59 of 124) of the postal group returned samples.

CONCLUSION

A randomised controlled trial comparing postal and opportunistic screening for chlamydial infection in general practice is feasible, although resource intensive. There may be problems with generalizing from screening trials in which patients may opt out from the offer of screening.

Chlamydia trachomatis in female sex workers in Belgium: 1998-2003

OBJECTIVE

We analysed the results of a 6 year screening period for Chlamydia trachomatis in a group of female sex workers (FSW) of all ages in Ghent, Belgium.

METHODS

They were tested in the context of an outreach health programme for sex workers. C trachomatis was tested by Cobas Amplicor CT/NG PCR.

RESULTS

In the 6 year period, 1643 tests were performed on 950 different sex workers (nationality: Belgian 60.3%, other western European (mostly French) 21.0%, African 12.4%, eastern European 3.0%, other 3.3%; workplace: bar/sauna 49.0%, private homes 31.8%, windows 18.2%, and escorts 1.0%). Baseline prevalence (only considering results of first test) was 70/950 or 7.4% (95% CI 5.7 to 9.0). The incidence rate was 98 episodes in 1347 person years or 7.3/100 person years (95% CI 5.9 to 8.7). There was a strong age effect. There was no clear relation with nationality or the workplace.

CONCLUSIONS

The prevalence was higher than in general populations selected in Belgium, Britain, and the Netherlands. Since younger age is a risk factor for C trachomatis, it is very important to contact these women as soon as possible when they enter the trade. General screening for C trachomatis in young women is not common practice in Belgium. Sex workers often do not tell doctors about their work and will therefore not be screened unless in the context of specific outreach projects.

Prevalence of urogenital Chlamydia trachomatis increases significantly with level of urbanisation and suggests targeted screening approaches: results from the first national population based study in the Netherlands

OBJECTIVES

Chlamydia trachomatis (Chlamydia) is the most prevalent sexually transmitted bacterial infection and can cause considerable reproductive morbidity in women. Chlamydia screening programmes have been considered but policy recommendations are hampered by the lack of population based data. This paper describes the prevalence of Chlamydia in 15-29 year old women and men in rural and urban areas, as determined through systematic population based screening organised by the Municipal Public Health Services (MHS), and discusses the implications of this screening strategy for routine implementation.

METHODS

Stratified national probability survey according to "area address density" (AAD). 21 000 randomly selected women and men in four regions, aged 15-29 years received a home sampling kit. Urine samples were returned by mail and tested by polymerase chain reaction (PCR). Treatment was via the general practitioner, STI clinic, or MHS clinic.

RESULTS

41% (8383) responded by sending in urine and questionnaire. 11% (2227) returned a refusal card. Non-responders included both higher and lower risk categories. Chlamydia prevalence was significantly lower in rural areas (0.6%, 95% CI 0.1 to 1.1) compared with very highly urbanised areas (3.2%, 95% CI 2.4 to 4.0). Overall prevalence was 2.0% (95% CI 1.7 to 2.3): 2.5% (95% CI 2.0 to 3.0%) in women and 1.5% (95% CI 1.1 to 1.8) in men. Of all cases 91% were treated. Infection was associated with degree of urbanisation, ethnicity, number of sex partners, and symptoms.

CONCLUSION

This large, population based study found very low prevalence in rural populations, suggesting that nationwide systematic screening is not indicated in the Netherlands and that targeted approaches are a better option. Further analysis of risk profiles will contribute to determine how selective screening can be done.

Cost-Effectiveness Analysis of Screening Adolescent Males for Chlamydia On Admission to Detention

BACKGROUND

Chlamydia trachomatis infections can lead to serious and costly sequelae. Because chlamydia is most often asymptomatic, many infected youth do not seek testing. Entry to a detention system provides an opportunity to screen and treat many at-risk youth. GOAL The goal of this study was to determine the cost-effectiveness of screening male youth for chlamydia on entry to detention.

STUDY DESIGN

Incremental cost-effectiveness of 3 chlamydia screening strategies was compared for a hypothetical cohort of 4000 male youth per year: 1) universal chlamydia screening using a urine-based nucleic acid amplification test (NAAT), 2) selective NAAT screening of urine leukocyte esterase (LE)-positive urines, and 3) no screening. The model incorporated programmatic costs of screening and treatment and medical cost savings from sequelae prevented in infected males and female partners. The analysis was conducted from the healthcare system perspective.

RESULTS

Chlamydia prevalence in the sampled population of 594 was 4.8%, and the average number of female sexual partners/infected male was 1.6. Universal NAAT screening was the most cost-effective strategy, preventing 37 more cases of pelvic inflammatory disease (PID) and 3 more cases of epididymitis than selective screening and saving an additional 24,000 dollars. The analysis was sensitive to NAAT cost, LE sensitivity, rate of PID development, PID sequelae cost, and number of female partners. Universal screening remained the most cost saving for prevalence as low as 2.8% or higher.

CONCLUSIONS

Universal chlamydia screening of adolescent males on entry to detention was the most cost-effective strategy. Savings are primarily the result of the prevention of PID in recent and future partners of index males. Screening detained male youth using a urine-based NAAT provides a public health opportunity to significantly reduce chlamydia infections in youth at risk for sexually transmitted diseases.

Prevalence of Chlamydia trachomatis infections and specimen collection preference among women, using self-collected vaginal swabs in community settings

BACKGROUND

Chlamydia trachomatis is a common, often asymptomatic sexually transmitted infection.

GOAL

The goal was to estimate the prevalence and predictors of C. trachomatis among young women using self-collected vaginal swabs, and the preferences of women and physicians for self-testing.

STUDY DESIGN

A total of 514 attendees of university/college health clinics, adolescent birth control clinics, centers providing health services to homeless youth and adults (street health centers), a sexually transmitted diseases clinic, and family practices were tested by ligase chain reaction. Preference for self- versus provider-testing was examined.

RESULTS

Prevalence was 6.0% and was highest (18.2%) in the street health centers. In multivariate analysis, only recent contact with someone with C. trachomatis infection was significantly associated with infection (odds ratio, 7.1; 95% confidence interval, 2.5-20.0). Most women (54.2%; 256 of 472) preferred self-sampling compared with physician sampling (15.9%; 75 of 472). The majority of physicians (75.0%; 9 of 12) reported at the start and end of the study that they would use vaginal swab self-sampling if available.

CONCLUSIONS

Prevalence of infection in young women attending homeless youth organizations was high. Self-sampling was acceptable and could facilitate screening in high-risk women who do not regularly access health services.

A refined estimate of the average lifetime cost of pelvic inflammatory disease

BACKGROUND

The major complications of pelvic inflammatory disease (infertility, ectopic pregnancy, and chronic pelvic pain) are the leading cause of non-HIV sexually transmitted disease morbidity in the United States.

GOAL

The goal of the study was to estimate a plausible range for the average lifetime cost of pelvic inflammatory disease (PID) and its major complications in a cohort of U.S. women of reproductive age.

STUDY DESIGN

We developed a state-transition computer-based model to simulate the natural history of PID, incorporating the severity of infection, number of recurrent episodes, treatment setting, and the risk over time of major complications. Clinical and cost data were from the published literature. Model outcomes included life expectancy, quality-adjusted life expectancy, and lifetime costs.

RESULTS

In a cohort of 100,000 females acquiring PID between 20 and 24 years of age, 8550 ectopic pregnancies, 16,800 cases of infertility, and 18,600 cases of chronic pelvic pain were projected to occur. Assuming a 3% annual discount rate, we found the average per-person lifetime cost to be $2150. Average lifetime costs for women who developed major complications were $6350 for chronic pelvic pain, $6840 for ectopic pregnancy, and $1270 for infertility. The majority of costs (79%) were accrued within 5 years of upper genital tract infection. Results were most sensitive to assumptions about the timing of major complications and the discount rate.

CONCLUSION

The average per-person lifetime cost of PID ranges between $1060 and $3180. Future cost-effectiveness analyses of STD screening programs can include this range as a reasonable upper and lower bound. These findings suggest successful PID prevention efforts may avert substantial costs for care providers such as managed care organizations while providing well documented clinical benefits for women in the United States.

Is the prevention of genital chlamydial infections by community involvement possible?

This chapter presents different means by which community initiatives have been undertaken to reduce the prevalence and incidence of genital and allied infections caused by Chlamydia trachomatis. As most of these infections in the majority of infected individuals do not produce symptoms that are likely to urge them to attend any health care unit, screening programmes are mandatory to be able to influence the epidemic of infections with this agent. In many societies there has been a skewed gender distribution in the number of chlamydia-positive persons; this probably indicates that diagnostic service activities have been directed more against one gender than the other. The important role of partner notification, as in the case of other sexually transmitted infections, has been documented. Different means of community initiative have included counselling of school children and groups of persons more likely to be infected. Counselling by the pharmacy has an important role in many societies. Selected cohorts have been offered - via the mass media, Internet, radio and television programmes - sampling kits which can be mailed to a laboratory for testing. The establishment of youth clinics has been found effective for detecting teenagers harbouring C. trachomatis, similarly to screening at antenatal clinics. The offer of free consultations, aetiological tests and therapy has been a part of community initiatives, mimicking the services offered for some of the classic sexually transmitted infections. This chapter considers the usefulness of different test methods and stresses the need to retest those found to be positive. Barriers to the successful introduction of screening activities and diagnostic services are also considered.

Evaluation of the Digene Hybrid Capture II Assay with the Rapid Capture System for detection of Chlamydia trachomatis and Neisseria gonorrhoeae

Screening for chlamydial and gonococcal infection has been strongly recommended for all sexually active women under the age of 26. Advances in the ability to detect infection by nucleic acid detection techniques have improved access to screening methods in routine clinical practices. To meet the increasing demand for testing, a high-throughput system is desirable. We evaluated the performance of the Hybrid Capture 2 CT/GC (HC2) assay with the Digene Rapid Capture System (HC2-RCS). The results of HC2-RCS for endocervical samples from 330 women were compared to those of culture and the COBAS Amplicor PCR. For detection of chlamydial infection, HC2-RCS had a sensitivity and a specificity similar to those of PCR (P > 0.5) and an improved sensitivity compared to that of culture (P = 0.007). For identification of gonococcal infections, all assays performed similarly (P > 0.5). The performance of HC2-RCS was also compared to that of the manual HC2 format (HC2-M) with these samples and with 911 endocervical samples collected previously. The performance of HC2-RCS was equivalent to that of HC2-M; the overall concordance rates for the detection of chlamydia and gonorrhea were 99.7% (kappa = 0.97) and 99.8% (kappa = 0.97), respectively. When the HC2 assay was performed with a semiautomated system application designed for high throughput, it demonstrated high sensitivity and a high specificity for detection of both Chlamydia trachomatis and Neisseria gonorrhoeae.

Chlamydia screening in primary care: is it useful, affordable and universal?

Genital chlamydial infection, with its possible long-term morbidity, is a serious public health problem. The number of new diagnoses is rising rapidly and, in the UK, recent evidence suggests that the infection rate in young women exceeds 10%. Screening programmes can reduce the population prevalence of infection, but uncertainty remains as to the ideal screening model. This may prove to be opportunistic screening of sexually active young women, less than 25 years of age, in primary care settings, and contact tracing of the partners of those with chlamydia. Recent literature on the practicalities of genital chlamydia screening is reviewed.